3.7. CTRP9 Overexpression Enhances Features of Atherosclerotic
Plaque Stability
In order to verify whether CTRP9 has a protective effect on
atherosclerosis, adeno-associated
virus was used to construct an animal model of CTRP9 overexpression. The
western blotting result showed that compared with AAV-GFP, AAV-CTRP9
significantly increased CTRP9 expression in Apoe-/-mice (Fig. 7e). To examine the effects of CTRP9 on atherosclerotic
plaque stability, we first analyzed the lesion sizes using HE staining.
Consistent with our previous study findings, CTRP9 reduced
atherosclerotic plaque size (Fig. 7a). To determine whether CTRP9
overexpression influences the features of plaque stability or not, we
performed Sirius Red staining to determine plaque collagen level. The
plaque collagen level, which plays an important structural role in
stabilizing plaques, was increased in CTRP9-overexpressed mice relative
to that in the control mice (Fig. 7b). Additionally, the number of
MYH11-positive cells was increased within plaques from
CTRP9-overexpressing mice relative to those from the controls, and this
is also consistent with increased plaque stability (Fig. 7c). Finally,
the expression of RIP3 was significantly decreased in plaque in
CTRP9-overexpressed mice relative to those from the control mice (Fig.
7d). Western blot was used to detect the expression of markers related
to necroptosis in mouse aorta. The results showed that overexpression of
CTRP9 significantly reduced the levels of p-RIP1, RIP3 and p-MLKL
compared with the control group (Fig.7e and f), which indicates that the
number of programmed necrotic cells in atherosclerotic plaque is
significantly reduced. In addition, we also detected the expression
levels of various inflammatory factors in the aorta. The results showed
that the expression of inflammatory factors in the aorta of
CTRP9-overexpressed mice was significantly decreased (Fig.7g). Overall,
these results demonstrate that CTRP9 promotes features of a stable
plaque phenotype in atherosclerosis.